Recently, a vehicle headlamp has been variously proposed as a structure in which a light source unit provided for light distribution formation and having a light emitting element as a light source is accommodated in a lamp chamber in order to reduce power consumption. Thus, a light emitting element capable of obtaining high luminous flux corresponding to the luminosity necessary for light distribution of a headlamp has been developed. However, in this case, the amount of heat generated by the light emitting element has become a problem. That is, in the light emitting element corresponding to the high luminous flux, the high luminous flux is obtained, whereas the amount of generated heat is correspondingly increased. As a result, there occur problems such as a decrease in luminous efficiency or a change in luminescent color.
For these reasons, various structures for increasing the cooling effect of the light emitting element have been proposed. For example, as disclosed in Japanese Patent Laid-Open Publication No. 2010-153333 (see FIGS. 2 and 4), a heat sink 9 is configured such that heat-dissipation fins 11 are formed behind a base plate 10 on which a light emitting element 3 and a reflector 2 are mounted, and thus, the heat generated by the light emitting element 3 is dissipated to the rear side of the heat sink 9.
Further, as disclosed in Japanese Patent Laid-Open Publication No. 2014-146463 (see FIG. 1), a cooling fan 12 is provided so as to directly face heat-dissipation fins 15 of a heat sink 11 on which a light emitting element 14 and a reflector 10 are mounted, thereby promoting the heat-dissipation.
However, in the above Patent Document 1, it is necessary to enlarge the heat-dissipation fins 11 of the heat sink 9 in order to increase the cooling effect of the light emitting element. Thus, the front-rear length of the light source unit is increased. However, there is a limit in relation to an accommodation space of the light source unit in a lamp chamber.
Further, in the above Patent Document 2, the cooling effect is increased by the flow of air generated by the cooling fan 12 without enlarging the heat-dissipation fins 15. However, the number of parts constituting the light source unit is increased. Accordingly, the configuration becomes complicated, the weight is increased, and the cost is also increased.